1. Field of the Invention
The present invention relates to a simple method for detection of atopic dermatitis, and to a kit for use in the method.
2. Discussion of the Related Art
Conventionally, atopic dermatitis has been diagnosed macroscopically or through detailed questioning on mainly clinical symptoms, such as morphologic features and distribution of skin rash, because there have been reported no detection methods for this disease. Clinical examination results are only used for references. For example, serum IgE levels are measured in clinical examination, a high IgE level providing a basis for the diagnosis of atopic dermatitis. It should be noted, however, that elevated IgE levels are observed not only in atopic dermatitis but also in other diseases including allergoses, such as bronchial asthma and allergic rhinitis; parasitic diseases; liver diseases, such as hepatitis, cirrhosis and primary hepatoma; and autoimmune diseases, such as systemic lupus erythematosus. Therefore, a high IgE value is not always directly associated with atopic dermatitis. On the contrary, there has been reported that a significant ratio of patients with atopic dermatitis have perfectly normal serum IgE levels.
Other methods of clinical examination include allergen detection tests, such as peripheral blood eosinophilic leukocyte counting, RAST method (antigen-specific IgE quantitation), scratch test, prick test, and patch test, none of which are necessarily specific to atopic dermatitis.
The above-mentioned methods of clinical examination are all based on the allergic aspects of atopic dermatitis. It is considered, however, that not only allergic aspects but also non-allergic aspects are important in atopic dermatitis.
The non-allergic aspects involve skin dysfunction. Hypofunction is observed in the skin, as a barrier separating the body from the outer environment, of patients with atopic dermatitis.
The ceramide, which accounts for about 50% of the intercorneocyte lipids in the corneal layer of skin, has been considered to protect the skin against drying and to play a key role in the barrier function. To date, a decrease in the ceramide contents has been observed in the skin of patients with atopic dermatitis, suggesting that this change may cause the tendency toward dry skin and a decrease in the barrier function. However, it has not been known why the ceramide contents decrease in the skin of patients with atopic dermatitis.
Also, there have been reported a decrease in the barrier function, and additionally an increase in the microbial cell counts in the skin of patients with atopic dermatitis, with reportedly an increase in the cell counts of various microorganisms, especially Staphylococcus aureus and Malassezia fungi. However, these microorganisms are commonly present on the skin, and no differences in the microbial properties have yet been demonstrated between microorganisms from normal individuals and from patients with atopic dermatitis, except for the increase in the cell counts. Also, with regard to microorganisms other than the major microorganisms Staphylococcus aureus and Malassezia fungi, no relationships to patients with atopic dermatitis have been demonstrated. No examination methods for atopic dermatitis based on such microbiological viewpoint have been available to date.
As described above, an examination method based on non-allergic aspects, i.e., viewpoints of microbiology and dermatopathy, would be very useful as a supplementary tool for the diagnosis of atopic dermatitis by the conventional examination method based on macroscopic observation or results of detailed questioning and allergic aspects, or as a method of primary screening for atopic dermatitis.
Accordingly, an object of the present invention is to provide a convenient method for detection of atopic dermatitis using samples from the skin.
Another object of the present invention is to provide a kit for use in the above method.
These and other objects of the present invention will be apparent from the following description.